Add setup function to improv_ble (#140594)

homeassistant/components/improv_ble/__init__.py

@@ -1 +1,11 @@
 """The Improv BLE integration."""
+
+from __future__ import annotations
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.core import HomeAssistant
+
+
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
+    """Set up improv_ble from a config entry."""
+    raise NotImplementedError